Self-locking box

ABSTRACT

A tray comprising, integrally connected, a bottom panel having bottom side panels and a front panel having front side panels, each front side panel being foldably connected at one edge to a bottom side panel and at its opposite edge to a locking panel, a locking flap formed in each of the bottom side panels and fold lines in said front side panels permitting the front panel and bottom side panels to be moved into erected position perpendicular to the bottom panel and the locking flaps to cooperate with the locking panels to secure the panels in erected position.

I United States Patent 1 3,58 1,976

[72] Inventor Norman E. Burgess 2,311,403 2/1943 Lighter 229/36X Westmount, Quebec, Canada 2,354,600 7/1944 Kretchner 1111 229/36X [21] Appl. No. 812,599 3,338,504 8/1967 Kossoffet al. 229/33 [22] Filed Apr. 2,1969 1,559,241 10/1925 Fox 229/41(A) {45] Patented June 1, 1971 3,371,842 3/1968 Aechtmann et al.... 229/33 [73] Assignee Dorntar Limited Primary ExammerDavis T. Moorhead Montreal Quebec Canada Attorney-C. A. Rowley [54] SELF-LOCKING BOX 5C1 l1 F alms Drawing ABSTRACT: A tray comprising, integrally connected, a bot- [52] US. Cl 229/36 tom pane] having bottom side panels and a from pane] having f 5 /2 front side panels, each front side panel being foldably con- [50] Field of 36, t d t d t a b t id panel d t it it 31, 33 edge to a locking panel, a locking flap formed in each of the bottom side panels and fold lines in said front side panels per- [56] References Cned mitting the front panel and bottom side panels to be moved UNITED STATES PATENTS into erected position perpendicular to the bottom panel and 1,321,727 11/1919 Fitzsimmons 229/36 the locking flaps to cooperate with the locking panels to 2,252,023 8/1941 Mulnix 229/31X secure the panels in erected position.

PATENIEU JUN Han 3581.976

- SHET10F2 INVENTOR Norman E. BURGESS AGENT PATENTED JUN nan V 3581.976

' same or 2 INVENTOR Norman E. BURGESS 4 AGEN 1 SELF-LOCKING BOX turer, butis easily set up with a simple twist of the wrists thereby to form an erected tray.

It is thus the main object of the present invention to provide a new form of self-locking box structure that does not require adhesives.

Broadly, the present invention comprises a bottom and a front panel, bottom side panels connected one to each side of said bottom panel, and front side panels connected one to each side of said front panel, said bottom side and said front side panels being foldably connected together along one end edge, a pair of fold lines extending from each corner of each of said front sidewall panels adjacent the juncture of this panel with the front panel to meet at the juncture of the center line of each said front side panel with the free edge of same, and a locking panel connected to the end of each said front side panel remote from said bottom side panel, a pair of locking flaps each formed by a slit in one of said bottom side panels and a hook formed on each said locking panel, said locking flaps and said hooks cooperating to hold said bottom and front panels in erected position.

Further features, objects and advantages will be evident from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a plan view of a blank formed in accordance with the present invention.

FIG. 2 is a partial plan view illustrating the first step in setting up of the carton.

FIG. 3 is an end view of FIG. 2.

FIG. 4 is a'partial isometric view illustrating the next step in setting up the tray section of the carton.

FIG. 5 is an end view of the carton illustrated in FIG. 4.

FIG. 6 is a partial isometric view of one corner of the tray structure in the final stages of erection.

FIG. 7 is a view looking in the direction of arrow a in FIG. 6.

FIG. 8 is an isometric viewof the partially setup carton illustrating the next folding operations for closing of the carton.

FIG. 9 is a partial isometric view illustrating the next stage in the closing operation.

FIG. 10 is an end view of an almost closed carton.

FIG. 11 is an isometric view of a closed carton.

The blank 10 of FIG. 1 comprises a top wall panel 12, a rear wall panel. 14, a bottom wall panel 16, a front wall panel 18, and a ledge forming panel 20, interconnected by fold lines 22, 24, 26 and 28. A pair of top outside side panels 30 are connected one to each side of top panel 12 by a fold line 32, and connected to each panel 30.by a fold line 34 which extends substantially perpendicular to the fold line 32, but spaced from the fold line 22 in a direction away frompanel 14 by a distance substantially equal to the thickness of the board, is a rear inside flap 36. No flaps or panels are connected to the rear wall panel 14. A pair of bottom inside side panels 38, and a pair of front side panels 40, are connected one to each opposite side of the panels l 6and 18 respectively by a pair of fold lines 42. Each of the panels 38 is hingedly connected to its adjacent panel 40 by an extension of fold line 22. A air of lock forming panels-44 are connected one to each end of the panel 20 by fold lines 46, and to their adjacent panel 40 by an extension of the fold line 28.

A locking slot 48 is cut into each of the top side panels 30 to form a locking tab 50-between slot 48 and the free end edge 52 of each panel 30. The slot 48 and tabs 50 cooperate with other parts of the carton to hold the box closed in a manner to be described more fully hereinbelow.

Each panel 38 has a substantially C-shaped slit 54 which, in the illustrated embodiment, begins at the free edge 56 of the panel 38 and terminates at or adjacent a fold line 58. The foldline 58 extends between the free edge 56 and the slit 54 to define with the slit 54 a locking flap 60 foldable relative to the panel 38 on fold line 58. The dimensions of this C-saped slit 54, the location of the slit 54 and of the fold line 58, the width of the locking panel 44, and the width of tab 50, are correlated for intercooperation to lock the tray in erected position and to hold the top of the box closed as will be more apparent as the description proceeds. The free edge 62 of the remainder of the panel 38 curves from the slit 54 to the fold line 26.

Each panel 40, in the illustrated embodiment, has a V- shaped free edge 64 with the leg of the V extending toward the fold line 26 being shortest. The specific shape of this free edge is important only to ensure that during erection the locking panel 44 is able to pass over the shorter leg of the V and into the box structure. Stated differently, it is important that the junction of the free edge 64 with the extension of fold line 26 be located at a point where it will not interfere with the movement of the panei 44 into the carton. Each of the panels 40 has a pair of fold lines 72 and 74 extending at an angle from the comers of the panel 40 adjacent the fold lines 26, 28 and 42 and meeting at a point on the free edge 64, which point is on the center line of the panels 18 and 40. These fold lines 72 and- 74 divide the panels in the illustrated embodiment into three triangular areas indicated at 66, 68 and 70.

The locking panels 44 are each provided on their free end edge remote from the fold line 28 with a hooklike projection 76 formed with an inwardly facing concave curved edge 78 adapted to receive an engage the bottom edge of the locking flap 60 and thereby lock the panels 18 and 20 in erected position as will be explained in detail hereinbelow.

To set up the carton, the blank is taken with both hands and pressure is applied to the triangular areas 68 of the panels 40 in the direction of the arrow 80 (preferably by means of the center fingers of each hand), as shown in FIGS. 2 and 3 thereby to fold the panels 38, 40 and 44 perpendicular to their respective panels 16, 18 and 20 on fold lines 42 and 46. The area 68 is moved past the perpendicular position to approach the inside surface of the panel l8 by continued pressure in the direction of the arrow 80 and by simultaneously bending (by thumb pressure) the panel 20 relative to panel 18 on fold line 28. Also simultaneously with the folding of the panels 40 and 20, the panel 18 may be folded relative to the panel 16 along the line 26 by twisting the wrists so that the end of the carton is shaped as shown in FIGS. 4 and 5 and finally to the position shown in FIGS. 6 and 7. As seen in FIGS. 4 and 5, the panel 44 slides over the top edge 65 of the panel 40 so that in the erected carton the panel 44 is positioned inside the panel 38 and the fold line 28 between the panels 40 and 44 is inside the fold line 26 between the panels 38 and 40. When the panels 18, 20, 38 and 40 have been folded to their final position with the panel 18 substantially perpendicular to the panels 16, 20 and 38 as shown in FIGS. 6, 7 and 8, the flaps 60 are folded on their fold lines 58 (preferably by means of the first finger of each hand) into the carton so that the bottom edge of each flap 60 overlies and engages the concave curved edge 78 of the projection 78 on the adjacent panel 44 thereby to lock the panels 18, 20, 38 and 40 in erected position.

In closing the box the panels 30 are folded perpendicular to the panel l2 along fold lines 32 and the flaps 36 are folded perpendicular to the panels 30 along fold lines 34 so that the carton is substantially as shown in FIG. 8. Next the panels 12 and 14 are folded along lines 22 and 24 relative to the panel 16 to the position shown in FIGS. 9, l0 and finally 11. As the box is closed, the panels 30 remain outside of the panels 38 and the tabs 50 are inserted inside of the panels 38 in the area between the fold lines 26 and 58. The slot 48 combines with the slit 54 so that the tab 50 may be located on one side of the panel 38, while the remainder of the panels 30 are outside of this panel. The tab 50 is snugly received between the inside surface of the panel 38 and the outside surface of thepanel 44 to lock the top in closed position substantially as shown in FIG. 11.

Thus applicant has disclosed a new folding carton that may be easily set up and closed without the use of adhesive. Modifications may be made without departing from the spirit of the invention as defined in the appended claims. For example, the tabs 50 could be turned to face in the opposite direction and the panels 30 folded to lie inside of the panels 38 with the tabs 50 on the outside. Also the panel could be omitted, however, setting up then becomes more difficult.

I claim:

1. A carton comprising a bottom panel and a front panel interconnected by a first fold line, a pair of bottom side panels foldably connected one to each side of said bottom panel, locking flaps formed by a slit in each of said bottom side panels and connected to said bottom side panels by fold lines, a ledge forming panel foldably connected to said front panel by a fold line substantially parallel to said first fold line, a pair of locking panels, means foldably connecting said ledge forming panel to each of said locking panels whereby said locking panels may be folded substantially perpendicular to said ledge forming panel, a locking hook projecting from a side edge of each said locking panel remote from said front panel, each said locking flap being foldable out of the plane of its respective bottom side panel on its said fold line connecting same to its respective bottom side panel into a position overlying said locking hook on its adjacent said locking panel.

2. A carton as defined in claim 1 further comprising a rear panel foldably connected to said bottom panel and a top panel foldably connected to said rear panel by fold lines substantially parallel to said first fold line.

3. A carton as defined in claim 2 further comprising top side panels foldably connected one at each side of said top panel, a locking slot extending in from the free side edge of each said top side panel adjacent the free end edge thereof and forming a locking tab between said slot and said free end edge, said slit and said slot cooperating to permit each said top side panel to be positioned on one side of its adjacent said bottom side panel with each said locking tab being positioned on the other side of said adjacent bottom side panel thereby to lock said top panel in closed position.

4. A carton as defined in claim 3 wherein said one side is the outside of the carton.

5. A carton as defined in claim 4 further comprising a pair of top rear flaps foldably connected one to the side of each said top side panel remote from said free edge. 

1. A carton comprising a bottom panel and a front panel interconnected by a first fold line, a pair of bottom side panels foldably connected one to each side of said bottom panel, locking flaps formed by a slit in each of said bottom side panels and connected to said bottom side panels by fold lines, a ledge forming panel foldably connected to said front panel by a fold line substantially parallel to said first fold line, a pair of locking panels, means foldably connecting said ledge forming panel to each of said locking panels whereby said locking panels may be folded substantially perpendicular to said ledge forming panel, a locking hook projecting from a side edge of each said locking panel remote from said front panel, each said locking flap being foldable out of the plane of its respective bottom side panel on its said fold line connecting same to its respective bottom side panel into a position overlying said locking hook on its adjacent said locking panel.
 2. A carton as defined in claim 1 further comprising a rear panel foldably connected to said bottom panel and a top panel foldably connected to said rear panel by fold lines substantially parallel to said first fold line.
 3. A carton as defined in claim 2 further comprising top side panels foldably connected one at each side of said top panel, a locking slot extending in from the free side edge of each said top side panel adjacent the free end edge thereof and forming a locking tab between said slot and said free end edge, said slit and said slot cooperating to permit each said top side panel to be positioned on one side of its adjacent said bottom side panel with each said locking tab being positioned on the other side of said adjacent bottom side panel thereby to lock said top panel in closed position.
 4. A carton as defined in claim 3 wherein said one side is the outside of the carton.
 5. A carton as defined in claim 4 further comprising a pair of top rear flaps foldably connected one to the side of each said top side panel remote from said free edge. 